Bottles app

I used the bottles app by pick n pay to buy some groceries. Groceries were delivered and after a while I realized that there was a refill aromat box I had ordered but had not seen. I immediately checked my bottles app to see if they had notified me that it was out of stock and would not be delivered but nothing. So I messaged them on the app and asked how come I did not receive the item. They tell me that it was out of stock and are prepared to refund me. So my question to them was , had I not noticed would you have refunded me? Because such small things one doesn't notice and because you trust in the company one won't do a thorough stock take. My next question was how many people has this happened to? Because I had packed my groceries and continued with my day until I realized that the aromat was not there, if I had not realized it then they would have just pocketed the 36 rand. How many people has this happened to? How many people ddnt realise or report this.